Improvement in artificial decoloring compounds



UNITED STATES PATENT @rrrcrt.

FRANCIS GERAU, OF NEW YORK, N. Y.

IMPROVEMENT IN ARTIFICIAL DECOLORING COMPOUNDS.

Specification forming part of Letters Patent No. I4,9I 1, dated May 20, 1856.

To all whom it may concern:

Be it known that I, FRANCIS GERAU, ofNeW York city, in the county of New York, in the State of New York, have invented an Artificial Bone-Black, intended for the same purposes as the natural bone-black; and I do hereby declare that the following'is a full and exact description of its manufacture.

The nature of my invention consists in subjecting to red heat in well-closed vessels a mixture of precipitated phosphate of lime, bituminous coal, and clay, generally in equal proportions.

. To enable others skilled in chemical operations to use my invention, I will proceed to dedescribe the materials and the way to work them.

The most important ingredient which imparts to the coal its characteristic qualities, the precipitated phosphate of lime, is had by precipitating a solution of phosphate of lime in muriatic acid by diluted lime-water. Care should be taken that the acidity be not entirely saturated, or atleast no considerable surplus of lime be used. The more thoroughly caustic the lime is the better for the result, and a much more powerful coal will be produced when the lime is suspended in a larger quantity of water. A solution of phosphate of lime may be had by macerating bones in muriatic acid for the purpose ofmanufacturing boneglue after Darcets method-the way which I intend to use for the present. This precipitate of phosphate of lime maybe mixed with the other ingredients either in a moist or dry state, according to which of both maybefound most convenient for a complete mixture.- Of the different kinds of coal those will be preferable which, when powdered, will meltin the fire-to some degree and make one entire coke a baking-coal then, so as to give the article the necessary hardness. Of those I have tried the Liverpool coal is the best suited for most purposes. Cumberland coal will do if a more porous coal is wanted; but the English cannel-coal is much more preferable for that purpose in point of power, and the so-called American cannel-coal has about the same effeet. The coal should be used as the finest powder, as well as the clay, which should better be white clay, and the ingredients must be mixed as thoroughly as possible. I usually take equal proportions of each, the phosphate of lime calculated as if in aperfectly dry state; but I do not bind myself to such proportions, as it must in some measure depend on the price of thematerialshow to producethe cheapest article, an additional quantity of phosphate of lime ameliorating the article, as well as a greater dilution of thelime-water for precipitating; and, further, as a phosphate oflimo precipitated by some alkali or carbonate of an alkali those of wood-ashes, for example, in case they can be had at a low price, would increase the power of the article considerably and al low a proportionate reduction of this ingredient. A greater proportion of clay will give a more compact coal 3 but one-half of the quantity of earth of the other two ingredients will be sufficient in producing the same sum total of power, when compactness is not cared for, which quality may be still increased by adding a minimum of molasses, or of the poorest sugar residuessay about one-twentieth to one-tenth per cent. of the whole weight of the ingredients. This mixture wants to be formed, by means of a suffieient quantity of water, into lumps of not so large a size, which, after being dried, are heated red hot in well-closed vessels until no gas is longer produced.

What I claim, then, as my invention, and desire to secure by Letters Patent, is

The use of phosphate of lime precipitated out of a solution in muriatic acid as an ingredient in a compound of materials for the manufacture of a decelerating-coal, which other materials may be varied according to circumstances. And I will mention particularly that I do not claim the use of phosphate of lime as such and in general, as it is found in burned bones and has lately been discovered in large alluvia; but it is the phosphate of lime in that particular state of precipitation, which state alone affords to the coal its main properties, and which is entirely difi'erent from the former by these three characteristics First, the method by which it is done is by precipitating an acid solution by some alkali or alkaline earth second, corresponding to this, the greatest difference in its physical properties, it being very voluminous, porous, retaining the water with great force, and for those very reasons exactly eminently fit for the production of a' decolorating-coal by keeping the particles of the combustible substance apart in melting, while the natural phosphate of lime of burned bones is compact, and after my experiments hardly any better for said purpose than any fine-ground mineral powder as carbonate of lime; and if I may compare it to analogous circumstances in other mineral substances, then the precipitated phosphate of lime may be said to differ from the calcined or natural, as the precipitated hydrate of the oxide of aluminum (A1 O HO) differs from the natural oxide (sapphire corindum ruby) or the hydrate after being made red hot, (A1 0 While, as I have found, the former one is a very good ingredient for an artificial bone-black, and even, so far as my knowledge goes, the only one fitfor that purpose besides precipitated phosphate of lime, the last one is not by any means better again than any other mineral powder or the natural clay--the silicate. So hydrated oxide of iron precipitated by caustic ammonia is a substance totally different in its physical and chemical properties in its relation to acids from the natural oxide or the former after red heat. Gold, silver, and platina, when precipitated out of a solution by another common metal, are very fine powders, entirely different in all their physical properties from the natural, regular, or the melted metal, while the precipitated platlna has the greatest condensing power for difl'erent gases, and thereby may produce the most energetic chemical process, and is in general technical use for some of those purposes. The common platina possesses only very little of this intrinsic quality; and, third, corresponding to this difference in their physical properties is the eminent difference in result when they are used in a mixture for an artificial decolorating-coal. While the precipitated phosphate of lime does furnish a superior and certainly, considering the expenses, the best article when manufactured after my method, the natural boneashes do, as a great many of my experiments did show, furnish a grayish coal not better than the common charcoal, and hardly deserving the denomination of decolorating; and all of the other propositions for artificial boneblack did not mention anything but the natural phosphate of lime of burned bones not dissolved and not precipitated, or as Payen did, the residue of bones after steam-boiling, for the manufacture of bone-glue after the common methodthat is, bones partially deprived by this proceeding of their cartilaginous matter-tl1erefore either bones unchanged, or the natural phosphate of lime undissolved.

FRANCIS GERAU.

Witnesses:

WM. RADDE,

RUDOLPH SCHRAMM. 

